Heme Oxygenase-1 Protects Retinal Endothelial Cells against High Glucose- and Oxidative/Nitrosative Stress-Induced Toxicity
Open Access
- 3 August 2012
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 7 (8), e42428
- https://doi.org/10.1371/journal.pone.0042428
Abstract
Diabetic retinopathy is a leading cause of visual loss and blindness, characterized by microvascular dysfunction. Hyperglycemia is considered the major pathogenic factor for the development of diabetic retinopathy and is associated with increased oxidative/nitrosative stress in the retina. Since heme oxygenase-1 (HO-1) is an enzyme with antioxidant and protective properties, we investigated the potential protective role of HO-1 in retinal endothelial cells exposed to high glucose and oxidative/nitrosative stress conditions. Retinal endothelial cells were exposed to elevated glucose, nitric oxide (NO) and hydrogen peroxide (H2O2). Cell viability and apoptosis were assessed by MTT assay, Hoechst staining, TUNEL assay and Annexin V labeling. The production of reactive oxygen species (ROS) was detected by the oxidation of 2′,7′-dichlorodihydrofluorescein diacetate. The content of HO-1 was assessed by immunobloting and immunofluorescence. HO activity was determined by bilirubin production. Long-term exposure (7 days) of retinal endothelial cells to elevated glucose decreased cell viability and had no effect on HO-1 content. However, a short-time exposure (24 h) to elevated glucose did not alter cell viability, but increased both the levels of intracellular ROS and HO-1 content. Moreover, the inhibition of HO with SnPPIX unmasked the toxic effect of high glucose and revealed the protection conferred by HO-1. Oxidative/nitrosative stress conditions increased cell death and HO-1 protein levels. These effects of elevated glucose and HO inhibition on cell death were confirmed in primary endothelial cells (HUVECs). When cells were exposed to oxidative/nitrosative stress conditions there was also an increase in retinal endothelial cell death and HO-1 content. The inhibition of HO enhanced ROS production and the toxic effect induced by exposure to H2O2 and NOC-18 (NO donor). Overexpression of HO-1 prevented the toxic effect induced by H2O2 and NOC-18. In conclusion, HO-1 exerts a protective effect in retinal endothelial cells exposed to hyperglycemic and oxidative/nitrosative stress conditions.This publication has 46 references indexed in Scilit:
- High glucose and interleukin-1β downregulate interleukin-1 type I receptor (IL-1RI) in retinal endothelial cells by enhancing its degradation by a lysosome-dependent mechanismCytokine, 2010
- Diabetic Retinopathy: Mitochondrial Dysfunction and Retinal Capillary Cell DeathAntioxidants and Redox Signaling, 2005
- Carbon monoxide mediates protection against nitric oxide toxicity in HeLa cellsFree Radical Biology & Medicine, 2005
- Effect of advanced glycation end products on accelerated apoptosis of retinal capillary cells under in vitro conditionsLife Sciences, 2005
- Heme Oxygenase-1 Induced in Müller Cells Plays a Protective Role in Retinal Ischemia–Reperfusion Injury in RatsInvestigative Ophthalmology & Visual Science, 2004
- Interaction between NO and COX pathways in retinal cells exposed to elevated glucose and retina of diabetic ratsAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2004
- Retinal endothelial cells are more susceptible to oxidative stress and increased permeability than brain-derived endothelial cellsMicrovascular Research, 2003
- Modulation of Endothelial Cell Apoptosis by Heme Oxygenase-1-Derived Carbon MonoxideAntioxidants and Redox Signaling, 2002
- OVEREXPRESSION OF HEME OXYGENASE PROTECTS RENAL TUBULAR CELLS AGAINST COLD STORAGE INJURYTransplantation, 2001
- H2O2and Genistein Differentially Modulate Protein Tyrosine Phosphorylation, Endothelial Morphology, and Monolayer Barrier FunctionBiochemical and Biophysical Research Communications, 1998